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Introduction

Units is a TypeScript library family for exact-arithmetic financial calculations using BigInt rationals.

Every number is stored as a numerator / denominator pair of BigInts — no floats, no rounding errors, no silent precision loss.

Why?​

// JavaScript floats
0.1 + 0.2 === 0.3 // false

// @table-q/units
GBP('0.10').add('0.20').eq('0.30') // true

Financial software cannot tolerate floating-point errors. @table-q/units eliminates them at the representation level.

Packages​

PackageDescription
@table-q/unitsCore library — units, values, arithmetic, rounding
@table-q/units-plugin-bignumberBigNumber.js integration for sqrt, log, etc.

Examples​

  • simple-math — Basic arithmetic with units. A starting point for exploring the core API.
  • uk-tax — UK PAYE tax calculation. Demonstrates financial domain-specific logic with HMRC test data.

Quick Start​

npm install @table-q/units
import { SCALAR } from '@table-q/units';

const GBP = SCALAR.clone({ kind: 'GBP', decimals: 2, signed: false });

const a = GBP('10.50');
const b = GBP('3.25');
console.log(a.add(b).toDecimal()); // '13.75'
console.log(a.div('3').mul('3').eq(a)); // true — exact fractions

// Handling dynamic input
const userAmount: string | number = getUserInput();
const value = GBP.parse(userAmount);